Analyte detection in physiological fluids, e.g., blood or blood-derived products, is of ever increasing importance for people who require monitoring of their analyte levels. Blood analyte measurement systems typically comprise an analyte meter that is configured to receive a biosensor, usually in the form of a test strip. A user may obtain a small sample of blood typically by a fingertip skin prick and then may apply the sample to the test strip to begin a blood analyte assay. Because many of these systems are portable, and testing can be completed in a short amount of time, patients are able to use such devices in the normal course of their daily lives without significant interruption to their personal routines. A person with diabetes may measure their blood glucose levels several times a day as a part of a self management process to ensure glycemic control of their blood glucose within a target range. Analyte detection assays find use in a variety of applications, including clinical laboratory testing, home testing, etc., where the results of such testing play a prominent role in diagnosis and management in a variety of disease conditions. Analytes of interest include glucose in diabetes management, cholesterol, and the like. In response to this growing importance of analyte detection, a variety of analyte detection protocols and devices have been developed for both clinical and home use.
One type of system that allows people to conveniently monitor their blood glucose levels includes a biosensor (e.g., a disposable test strip) for receiving a blood sample from a user, and a meter that reads the test strip to determine the glucose level in the blood sample. The test strip typically includes electrical contact pads, for engaging electrical contacts of the meter, and a sample chamber that contains reagents (e.g., glucose oxidase and a mediator) and electrodes to form an electrochemical cell. To begin the test, the test strip is inserted into the meter and the user applies a blood sample to the sample chamber. The analyte is allowed to react with the redox reagent to form an oxidizable (or reducible) substance in an amount corresponding to the blood analyte concentration. The quantity of the oxidizable (or reducible) substance present is then estimated electrochemically by applying a voltage signal to the reacted sample via the electrodes and measuring an electrical response which is related to the amount of analyte present in the initial sample. After the test is completed, the test strip can be discarded.
It should be emphasized that frequent measurements of blood glucose levels may be critical to the long-term health of many users. As a result, there is a need for blood glucose measuring systems that are reliable and easy to use.
Most analyte meters designed for home use are powered by batteries. There are occasions in which the batteries become depleted. In situations in which replacement batteries are not available, a user would not typically be able to conduct a test either as part of their typical regimen or instances (e.g., a heavy meal) in which a measurement should be taken.